Silver halide emulsion and method for producing same

Abstract

The invention provides a silver halide emulsion, comprising: silver halide grains containing silver chloride as a primary component and further containing silver bromide; wherein, when an average value of a silver bromide content of the silver halide grains is represented by Y (mol %), a silver bromide content of at least 68% of the silver halide grains is from 0.82×Y (mol %) to 1.18×Y (mol %). Further, the invention provides a method of producing the silver halide emulsion, comprising the step of reacting at least a silver ion, a chlorine ion and a bromine ion; wherein a growth speed at a time of forming a silver bromine-containing phase in the reaction process is at least 60% of a critical growth speed.

1. A silver halide emulsion, comprising: silver halide grains containing silver chloride as a primary component and further containing silver bromide and silver iodide; wherein, when an average value of a silver bromide content of the silver halide grains is represented by Y (mol %), a silver bromide content of at least 68% of the silver halide grains is from 0.82×Y (mol %) to 1.18×Y (mol %) and silver iodide content is 0.05 to 1 mole %. 
     
     
       2. The silver halide emulsion of  claim 1 , wherein a grain size distribution is no more than 20%. 
     
     
       3. The silver halide emulsion of  claim 1 , wherein a silver chloride content is at least 95 mol %. 
     
     
       4. The silver halide emulsion of  claim 1 , wherein the silver halide emulsion comprises a silver bromide-containing phase in which an average Br content is at least 18 mol %. 
     
     
       5. The silver halide emulsion of  claim 4 , wherein the silver bromide-containing phase includes a layer-shaped structure having a thickness of from 0.005 μm to 0.04 μm. 
     
     
       6. The silver halide emulsion of  claim 4 , wherein an average Br content of the silver bromide-containing phase is from 20 mol % to 32 mol %. 
     
     
       7. The silver halide emulsion of  claim 1 , wherein at least 50% of a projected area of the grains is trisoctahedral. 
     
     
       8. The silver halide emulsion of  claim 4 , wherein at least 50% of a projected area of the grains before the silver bromide-containing phase is formed is trisoctahedral. 
     
     
       9. The silver halide emulsion of  claim 1 , wherein the grains comprise silver iodide in the range of from 0.05 mol % to 0.4 mol %. 
     
     
       10. The silver halide emulsion of  claim 4 , wherein the grains before the silver bromide-containing phase is formed comprise silver iodide in the range of from 0.05 mol % to 0.4 mol %. 
     
     
       11. A method of producing a silver halide emulsion, comprising the step of reacting at least a silver ion, a chlorine ion and a bromine ion;
 wherein  
 a growth speed at a time of forming a silver bromine-containing phase in the reaction process is at least 60% of a critical growth speed; and  
 the silver halide emulsion comprises a silver halide grain containing silver chloride as a primary component and further containing silver bromide, wherein, when an average value of a silver bromide content of the silver halide grain is represented by Y (mol %), a silver bromide content of at least 68% of the silver halide grains is from 0.82×Y (mol %) to 1.18×Y (mol %).  
 
     
     
       12. The method of producing the silver halide emulsion of  claim 11 , wherein the growth speed is 70% or more of the critical growth speed. 
     
     
       13. The method of producing the silver halide emulsion of  claim 11 , wherein a grain size distribution of the silver halide grains is no more than 20%. 
     
     
       14. The method of producing the silver halide emulsion of  claim 11 , wherein the silver halide grain has a silver chloride content of at least 95 mol %, and the silver halide emulsion further comprises a silver bromide-containing phase wherein an average Br content is at least 18 mol %. 
     
     
       15. The method of producing the silver halide emulsion of  claim 14 , wherein a temperature at the time of forming the silver bromide-containing phase is no more than 38° C. 
     
     
       16. The siver halide emulsion of  claim 1 , wherein a siver content of the silver halide grains is at least 95 mole %, and siver bomide content is 1 to 5 mole %. 
     
     
       17. The method of producing the silver halide emulsion of  claim 11 , wherein the siver halide grains comprise silver iodide in the range of 0.05 to 1 mole %. 
     
     
       18. The method of producing the silver halide emulsion of  claim 17 , wherein the siver chloride content of the siver halide grains is at least 95 mole %, and the silver bromide content is 1 to 5 mole %.